The present application generally relates to exhaust aftertreatment systems, and in particular to exhaust aftertreatment systems including a selective catalytic reduction (SCR) for reducing NOx emissions. Modern internal combustion engine systems often utilize aftertreatment devices to treat the engine exhaust and reduce exhaust emissions. Commonly used devices include catalytic elements, such as oxidation catalysts, catalyzed particulate filters, and selective catalytic reduction (SCR) catalyst systems. Many catalytic elements have catalyst materials which are neutralized, deactivated, or experience reduced effectiveness when exposed to sulfur compounds over time. The deactivation by sulfur over time is an accumulative process, limiting the effective life of the catalytic component, or requiring periodic removal of the sulfur compounds.
The presence of sulfur decreases the efficiency of various components in the exhaust aftertreatment system. Presently known sulfur removal processes require exposing the SCR catalyst to very high temperatures, which may significantly impact fuel economy, mission performance of the engine, and expose the other exhaust aftertreatment system components to increased aging. Therefore, a need remains for further improvements in systems, apparatus, and methods for SCR aftertreatment systems.